Recently, a 2D array probe capable of displaying real time 3-dimensional ultrasound images has been developed for use with making diagnoses. This probe has an electronic circuit that controls transmission and reception via several thousand transducers.
Upon transmission, a delay time is set such that ultrasound wavefronts transmitted from the transducers are justified on a focal point, timing pulses based on the delay time are generated from a delay circuit of a timing pulse generator, and the timing pulses are output from output terminals to channels (signal paths to or from the transducer) of the transducers.
Subsequently, a high-frequency voltage pulse based on the timing pulse is output from the pulser to the transducer, thereby activating the transducer.
The timing pulse generator includes an ASIC (Application Specific Integrated Circuit) that unifies circuits having a plurality of functions including a delay circuit.
The timing pulse generator is housed in the case of the probe. Normally, the capacity of the case is about 100 cc only, necessitating that the circuit size of the timing pulse generator be preferably made as small as possible.
If the delay circuit is composed of a single circuit, the circuit size becomes larger. Therefore, as illustrated in FIG. 8, the delay circuit is composed of two common circuits, namely, a rough adjustment circuit for setting a rough delay time and a fine adjustment circuit for setting a more specific delay time than the rough delay time. Further, two kinds of circuits are provided for each group by dividing the arrayed transducer into a plurality of regions and dividing the timing pulse generator into a plurality of groups. Further, the groups are allowed to correspond to the regions (the region composed of a plurality of transducers.) In FIG. 8, some groups among the plurality of groups are illustrated by the codes G0 to G7. For example, the group G0 has a rough adjustment circuit for setting a delay time of 0 [μs] and a fine adjustment circuit for setting nine delay times at intervals of 0.1 [μs]. In other words, in the group G0, within a time range of 0 [μs] to 0.8 [μs], a delay time is assigned to the transducer within the region corresponding to the group G0. In addition, for example, the group G7 has a rough adjustment circuit for setting a delay time of 7.0 [μs] and a fine adjustment circuit for setting nine delay times at intervals of 0.1 [μs]. In other words, in the group G7, within a time range of 7.0 [μs] to 7.8 [μs], a delay time is assigned to the transducer within the region corresponding to the group G7. As described above, it is possible to make the delay time range different for each group. Thus, the delay time may be assigned to the transducer within the region by using two kinds of circuits in the group, thereby making each circuit compact and reducing the entire circuit size. Further, as the transducer corresponds to the channel, the region of the transducer may be sometimes referred to as the channel region.
The group of the timing pulse generator is selected, for example, in accordance with a diagnosis mode. In this case, the region corresponding to this group is unambiguously selected.